How in Unity, when you click on a button, the form for creating an application opens?

Question

Unity

(Example Avito, there, when clicked, a form opens and information about the product you want to sell is filled in it)

Answer 1

Make up the form, put it on the stage, turn it off, turn it on by pressing the button.
The second option - put in the prefab, by the button - instantiate the prefab.